Project 3: HIV and HIV Interventions to Promote Healthy Aging?Abstract Driven by the large-scale HIV treatment and prevention initiatives of the past, the HIV epidemic in sub- Saharan Africa (SAA) is aging rapidly. Three persistent knowledge gaps related to aging and HIV currently stand in the way of the long-term success of the HIV treatment and prevention response. First, the dynamics of the HIV treatment and prevention cascades in older adults are poorly understood. Second, very large proportions of older adults are unaware of their HIV status and it is currently unknown which approaches increase HIV testing and programmatic linkage in older adults. Third, the long-term causal impacts of HIV treatment among aging adults in SSA are unknown, in particular regarding dementia and physical and emotional functioning. The long-term goal is to ensure that the full potential impact of `real life' mass HIV treatment and prevention strategies in SSA is realized. The objective in this application is to identify approaches to improve the HIV response for older adults in SSA. Our central hypothesis is that large proportions of older adults are currently failing to benefit fully from HIV treatment and prevention in SSA, but that these failures can be successfully addressed through population- and health systems-based interventions. The rationale for the proposed research is that once it is known how older adults can be near-universally and successfully reached for HIV testing and programmatic linkage, and what the long-term impacts of HIV treatment among aging populations in SSA are, routine health policy and intervention strategies can be designed to ensure that older adults are fully benefiting from the HIV response in the region. Building on strong preliminary data based on work funded by a previous NIH/NIA P01 (P01-AG041710), this hypothesis will be tested by pursuing three specific aims: AIM 1: Quantify the longitudinal developments and determinants of the HIV prevention and treatment cascades among older adults in rural South Africa. AIM 2: Establish in a population-based randomized field experiment the impacts of alternative home- based HIV testing strategies on HIV status knowledge and intervention uptake. AIM 3: Establish through population-based quasi-experiments the long-term population impacts of HIV treatment on dementia and physical functioning. The approach is innovative, because it utilizes a longitudinal population-based health research infrastructure for population-based experiments and quasi-experiments. The proposed research is significant, because it is expected to advance our understanding how older adults can be better reached and served by effective HIV interventions. Ultimately, this understanding will ensure the long-term success of the HIV response in SSA.